4952

1 files changed, 450 insertions, 3 deletions

diff --git a/subx/058stream-equal.subx b/subx/058stream-equal.subx
index 5a01d7ff..e4c1962e 100644
--- a/subx/058stream-equal.subx
+++ b/subx/058stream-equal.subx
@@ -1,10 +1,12 @@
+# some primitives for checking stream contents
+
 == code
 #   instruction                     effective address                                                   register    displacement    immediate
 # . op          subop               mod             rm32          base        index         scale       r32
 # . 1-3 bytes   3 bits              2 bits          3 bits        3 bits      3 bits        2 bits      2 bits      0/1/2/4 bytes   0/1/2/4 bytes
 
 # main:
-#?     e8/call test-stream-data-equal/disp32
+#?     e8/call test-next-stream-line-equal-stops-at-newline/disp32
     e8/call  run-tests/disp32  # 'run-tests' is a function created automatically by SubX. It calls all functions that start with 'test-'.
     # syscall(exit, Num-test-failures)
     8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           3/r32/EBX   Num-test-failures/disp32          # copy *Num-test-failures to EBX
@@ -42,7 +44,7 @@ $stream-data-equal?:loop:
     # if (curr >= max) return true
     39/compare                      3/mod/direct    6/rm32/ESI    .           .             .           2/r32/EDX   .               .                 # compare ESI with EDX
     7d/jump-if-greater-or-equal  $stream-data-equal?:true/disp8
-    # AL = *s
+    # AL = *currs
     8a/copy-byte                    0/mod/indirect  6/rm32/ESI    .           .             .           0/r32/AL    .               .                 # copy byte at *ESI to AL
     # CL = *curr
     8a/copy-byte                    0/mod/indirect  7/rm32/EDI    .           .             .           1/r32/CL    .               .                 # copy byte at *EDI to CL
@@ -193,7 +195,7 @@ test-stream-data-equal-length-check:
     5d/pop-to-EBP
     c3/return
 
-# helper for tests
+# helper for later tests
 check-stream-equal:  # f : (address stream), s : (address string), msg : (address string)
     # . prolog
     55/push-EBP
@@ -223,3 +225,448 @@ check-stream-equal:  # f : (address stream), s : (address string), msg : (addres
     89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
     5d/pop-to-EBP
     c3/return
+
+# scan the next line until newline starting from f->read and compare it with
+# 's' (ignoring the trailing newline)
+# on success, set f->read to after the next newline
+# on failure, leave f->read unmodified
+# this function is usually used only in tests, so we repeatedly write f->read
+next-stream-line-equal?:  # f : (address stream), s : (address string) -> EAX : boolean
+    # pseudocode:
+    #   currf = f->read  # bound: f->write
+    #   currs = 0  # bound : s->length
+    #   while true
+    #     if currf >= f->write
+    #       return currs >= s->length
+    #     if f[currf] == '\n'
+    #       ++currf
+    #       return currs >= s->length
+    #     if currs >= s->length return false  # the current line of f still has data to match
+    #     if f[currf] != s[currs] return false
+    #     ++currf
+    #     ++currs
+    #
+    # collapsing the two branches that can return true:
+    #   currf = f->read  # bound: f->write
+    #   currs = 0  # bound : s->length
+    #   while true
+    #     if currf >= f->write break
+    #     if f[currf] == '\n' break
+    #     if currs >= s->length return false  # the current line of f still has data to match
+    #     if f[currf] != s[currs] return false
+    #     ++currf
+    #     ++currs
+    #   ++currf  # skip '\n'
+    #   return currs >= s->length
+    # Here the final `++currf` is sometimes unnecessary (if we're already at the end of the stream)
+    #
+    # registers:
+    #   f : ESI
+    #   s : EDI
+    #   currf : ECX
+    #   currs : EDX
+    #   f[currf] : EAX
+    #   s[currs] : EBX
+    #
+    # . prolog
+    55/push-EBP
+    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
+    # . save registers
+    51/push-ECX
+    52/push-EDX
+    56/push-ESI
+    57/push-EDI
+    # ESI = f
+    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           6/r32/ESI   8/disp8         .                 # copy *(EBP+8) to ESI
+    # currf/ECX = f->read
+    8b/copy                         1/mod/*+disp8   6/rm32/ESI    .           .             .           1/r32/ECX   4/disp8         .                 # copy *(ESI+4) to ECX
+    # EDI = s
+    8b/copy                         1/mod/*+disp8   5/rm32/EBP    .           .             .           7/r32/EDI   0xc/disp8       .                 # copy *(EBP+12) to EDI
+    # currs/EDX = 0
+    31/xor                          3/mod/direct    2/rm32/EDX    .           .             .           2/r32/EDX   .               .                 # clear EDX
+    # EAX = EBX = 0
+    31/xor                          3/mod/direct    0/rm32/EAX    .           .             .           0/r32/EAX   .               .                 # clear EAX
+    31/xor                          3/mod/direct    3/rm32/EBX    .           .             .           3/r32/EBX   .               .                 # clear EBX
+$next-stream-line-equal?:loop:
+    # if (currf >= f->write) break
+    3b/compare                      0/mod/indirect  6/rm32/ESI    .           .             .           1/r32/ECX   .               .                 # compare ECX with *ESI
+    7d/jump-if-greater-or-equal  $next-stream-line-equal?:break/disp8
+    # AL = *(f->data + f->read)
+    8a/copy-byte                    1/mod/*+disp8   4/rm32/sib    6/base/ESI  1/index/ECX   .           0/r32/AL    0xc/disp8       .                 # copy byte at *(ESI+ECX+12) to AL
+    # if (EAX == '\n') break
+    81          7/subop/compare     3/mod/direct    0/rm32/EAX    .           .             .           .           .               0xa/imm32/newline # compare EAX
+    74/jump-if-equal  $next-stream-line-equal?:break/disp8
+    # if (currs >= s->length) return false
+    3b/compare                      0/mod/indirect  7/rm32/EDI    .           .             .           2/r32/EDX   .               .                 # compare EDX with *EDI
+    7d/jump-if-greater-or-equal  $next-stream-line-equal?:false/disp8
+    # BL = *(s->data + currs)
+    8a/copy-byte                    1/mod/*+disp8   4/rm32/sib    7/base/EDI  2/index/EDX   .           3/r32/BL    4/disp8         .                 # copy byte at *(EDI+EDX+4) to BL
+    # if (EAX != EBX) return false
+    39/compare                      3/mod/direct    0/rm32/EAX    .           .             .           3/r32/EBX   .               .                 # compare EAX and EBX
+    75/jump-if-not-equal  $next-stream-line-equal?:false/disp8
+    # ++currf
+    41/increment-ECX
+    # ++currs
+    42/increment-EDX
+    eb/jump $next-stream-line-equal?:loop/disp8
+$next-stream-line-equal?:break:
+    # ++currf
+    41/increment-ECX
+    # if currs >= s->length return true
+    3b/compare                      0/mod/indirect  7/rm32/EDI    .           .             .           2/r32/EDX   .               .                 # compare EDX with *EDI
+    7c/jump-if-lesser  $next-stream-line-equal?:false/disp8
+$next-stream-line-equal?:true:
+    b8/copy-to-EAX  1/imm32
+    # persist f->read on success
+    89/copy                         1/mod/*+disp8   6/rm32/ESI    .           .             .           1/r32/ECX   4/disp8         .                 # copy ECX to *(ESI+4)
+    eb/jump  $next-stream-line-equal?:end/disp8
+$next-stream-line-equal?:false:
+    b8/copy-to-EAX  0/imm32
+$next-stream-line-equal?:end:
+    # . restore registers
+    5f/pop-to-EDI
+    5e/pop-to-ESI
+    5a/pop-to-EDX
+    59/pop-to-ECX
+    # . epilog
+    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
+    5d/pop-to-EBP
+    c3/return
+
+test-next-stream-line-equal-stops-at-newline:
+    # . prolog
+    55/push-EBP
+    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
+    # clear-stream(_test-stream)
+    # . . push args
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  clear-stream/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
+    # write(_test-stream, "Abc\ndef")
+    # . write(_test-stream, "Abc")
+    # . . push args
+    68/push  "Abc"/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  write/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # . write(_test-stream, Newline)
+    # . . push args
+    68/push  Newline/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  write/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # . write(_test-stream, "def")
+    # . . push args
+    68/push  "def"/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  write/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # EAX = next-stream-line-equal?(_test-stream, "Abc")
+    # . . push args
+    68/push  "Abc"/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  next-stream-line-equal?/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # check-ints-equal(EAX, 1, msg)
+    # . . push args
+    68/push  "F - test-next-stream-line-equal-stops-at-newline"/imm32
+    68/push  1/imm32
+    50/push-EAX
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+    # . epilog
+    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
+    5d/pop-to-EBP
+    c3/return
+
+test-next-stream-line-equal-stops-at-newline-2:
+    # . prolog
+    55/push-EBP
+    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
+    # clear-stream(_test-stream)
+    # . . push args
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  clear-stream/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
+    # write(_test-stream, "Abc\ndef")
+    # . write(_test-stream, "Abc")
+    # . . push args
+    68/push  "Abc"/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  write/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # . write(_test-stream, Newline)
+    # . . push args
+    68/push  Newline/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  write/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # . write(_test-stream, "def")
+    # . . push args
+    68/push  "def"/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  write/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # EAX = next-stream-line-equal?(_test-stream, "def")
+    # . . push args
+    68/push  "def"/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  next-stream-line-equal?/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # check-ints-equal(EAX, 0, msg)
+    # . . push args
+    68/push  "F - test-next-stream-line-equal-stops-at-newline-2"/imm32
+    68/push  0/imm32
+    50/push-EAX
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+    # . epilog
+    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
+    5d/pop-to-EBP
+    c3/return
+
+test-next-stream-line-equal-skips-newline:
+    # . prolog
+    55/push-EBP
+    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
+    # clear-stream(_test-stream)
+    # . . push args
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  clear-stream/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
+    # write(_test-stream, "Abc\ndef\n")
+    # . write(_test-stream, "Abc")
+    # . . push args
+    68/push  "Abc"/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  write/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # . write(_test-stream, Newline)
+    # . . push args
+    68/push  Newline/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  write/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # . write(_test-stream, "def")
+    # . . push args
+    68/push  "def"/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  write/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # . write(_test-stream, Newline)
+    # . . push args
+    68/push  Newline/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  write/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # next-stream-line-equal?(_test-stream, "Abc")
+    # . . push args
+    68/push  "Abc"/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  next-stream-line-equal?/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # EAX = next-stream-line-equal?(_test-stream, "def")
+    # . . push args
+    68/push  "def"/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  next-stream-line-equal?/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # check-ints-equal(EAX, 1, msg)
+    # . . push args
+    68/push  "F - test-next-stream-line-equal-skips-newline"/imm32
+    68/push  1/imm32
+    50/push-EAX
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+    # . epilog
+    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
+    5d/pop-to-EBP
+    c3/return
+
+test-next-stream-line-equal-handles-final-line:
+    # . prolog
+    55/push-EBP
+    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
+    # clear-stream(_test-stream)
+    # . . push args
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  clear-stream/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
+    # write(_test-stream, "Abc\ndef")
+    # . write(_test-stream, "Abc")
+    # . . push args
+    68/push  "Abc"/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  write/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # . write(_test-stream, Newline)
+    # . . push args
+    68/push  Newline/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  write/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # . write(_test-stream, "def")
+    # . . push args
+    68/push  "def"/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  write/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # next-stream-line-equal?(_test-stream, "Abc")
+    # . . push args
+    68/push  "Abc"/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  next-stream-line-equal?/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # EAX = next-stream-line-equal?(_test-stream, "def")
+    # . . push args
+    68/push  "def"/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  next-stream-line-equal?/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # check-ints-equal(EAX, 1, msg)
+    # . . push args
+    68/push  "F - test-next-stream-line-equal-skips-newline"/imm32
+    68/push  1/imm32
+    50/push-EAX
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+    # . epilog
+    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
+    5d/pop-to-EBP
+    c3/return
+
+test-next-stream-line-equal-always-fails-after-eof:
+    # . prolog
+    55/push-EBP
+    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
+    # clear-stream(_test-stream)
+    # . . push args
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  clear-stream/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
+    # write nothing
+    # EAX = next-stream-line-equal?(_test-stream, "")
+    # . . push args
+    68/push  ""/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  next-stream-line-equal?/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # check-ints-equal(EAX, 0, msg)
+    # . . push args
+    68/push  "F - test-next-stream-line-equal-always-fails-after-eof"/imm32
+    68/push  1/imm32
+    50/push-EAX
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+    # EAX = next-stream-line-equal?(_test-stream, "")
+    # . . push args
+    68/push  ""/imm32
+    68/push  _test-stream/imm32
+    # . . call
+    e8/call  next-stream-line-equal?/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # check-ints-equal(EAX, 0, msg)
+    # . . push args
+    68/push  "F - test-next-stream-line-equal-always-fails-after-eof/2"/imm32
+    68/push  1/imm32
+    50/push-EAX
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+    # . epilog
+    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
+    5d/pop-to-EBP
+    c3/return
+
+# helper for later tests
+check-next-stream-line-equal:
+    # . prolog
+    55/push-EBP
+    89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
+    # . save registers
+    50/push-EAX
+    # EAX = next-stream-line-equal?(f, s)
+    # . . push args
+    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0xc/disp8       .                 # push *(EBP+12)
+    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           8/disp8         .                 # push *(EBP+8)
+    # . . call
+    e8/call  next-stream-line-equal?/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+    # check-ints-equal(EAX, 1, msg)
+    # . . push args
+    ff          6/subop/push        1/mod/*+disp8   5/rm32/EBP    .           .             .           .           0x10/disp8      .                 # push *(EBP+16)
+    68/push  1/imm32
+    50/push-EAX
+    # . . call
+    e8/call  check-ints-equal/disp32
+    # . . discard args
+    81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+    # . restore registers
+    58/pop-to-EAX
+    # . epilog
+    89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
+    5d/pop-to-EBP
+    c3/return